title: Global dot integration in typically developing children and in Williams syndrome.
abstract: Williams Syndrome (WS) is a neurodevelopmental disorder that results in deficits in visuospatial perception and cognition. The dorsal stream vulnerability hypothesis in WS predicts that visual motion processes are more susceptible to damage than visual form processes. We asked WS participants and typically developing children to detect the global structure Glass patterns, under "static" and "dynamic" conditions in order to evaluate this hypothesis. Sequentially presented Glass patterns are coined as dynamic because they induce illusory motion, which is modeled after the interaction between orientation (form) and direction (motion) mechanisms. If the dorsal stream vulnerability holds in WS participants, then they should process real and illusory motion atypically. However, results are consistent with the idea that form and motion integration mechanisms are functionally delayed or attenuated in WS. Form coherence thresholds for both static and dynamic Glass patterns in WS were similar to those of 4-5year old children, younger than what is predicted by mental age. Dynamic presentation of Glass patterns improved thresholds to the same degree as typical participants. Motion coherence thresholds in WS were similar to those of mental age matches. These data pose constraints on the dorsal vulnerability hypothesis, and refine our understanding of the relationship between form and motion processing in development.
authors.affiliation: Department of Psychology, University of South Carolina, 1512 Pendleton Street, Columbia, SC 29208, United States. Electronic address: mcp@ski.org.
authors.forename: Melanie
authors.initials: M
authors.lastname: Palomares
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Shannon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005556:Form Perception / Q000502:physiology; D006801:Humans; D009039:Motion Perception / Q000502:physiology; D010364:Pattern Recognition, Visual; D013028:Space Perception / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D018980:Williams Syndrome / Q000503:physiopathology*; D055815:Young Adult
keywords: Development; Form processing; Glass patterns; Global integration; Illusory motion; Motion processing; Williams Syndrome